Methods and compositions for the treatment and prevention of cancer

ABSTRACT

The instant invention provides compositions for the treatment of cancer. Specifically, the invention provides polypeptides and nucleic acid molecules comprising tumor-associated embryonic antigens, e.g., OFA-iLRP, and chemoattractant ligands, e.g., a proinflammatory chemokine such as MIP3α/CCL20 or β-defensin mDF2β. The invention further provides cancer vaccines and methods for treating subjects having, or at risk of developing, cancer.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 11/899,165, filed Sep. 3, 2007, now U.S. Pat. No. 8,258,278, which claims the benefit of U.S. Provisional Application No. 60/841,927, filed Sep. 1, 2006. The aforementioned patent applications are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

The basis for the high expectations of cancer immunotherapy is in its ability to eliminate the residual malignant cells and prevent relapse of the disease. The simplest method is to induce tumor-specific immunity by immunizing patients with the antigenic components of their tumors, so called tumor-associated antigens (TAAs). However, TAAs are often poorly immunogenic and their repertoire for immunotherapeutic use is quite limited. Unlike solid tumors, immunotherapy for B cell malignancies is further hampered by lack of well defined TAAs, except for the patient's unique idiotypic antibody (Id). Although efficacy of the Id vaccines both in preclinical studies and phase I-II clinical tests is demonstrably potent², a broader application of the vaccines may not be feasible due to the unpredictability of their T cell epitopes³, needed for T cell responses, and the suppressive nature of tumor derived Id in the absence of continuing T cell help⁴. In addition, Id vaccines have to be custom tailored and individually produced for each patient. Idiotypic vaccines for some B cell malignancies have been shown to be effective both in animal models^(9;32-34) and in phase I-III clinical trials³⁵. However, a major limitation of this method is not only that the vaccine is individually produced for each patient (see review^(36;37)), but also that the T cell epitopes essential for the protection may not always be expressed on Id.

Recently, the oncofetal Ag-immature laminin receptor 37-kDa protein, OFA-iLRP, was reported to be specifically expressed in different human tumors, such as breast, renal, lung and ovarian cancers, and in hematological malignancies¹. OFA exists in two forms, as the dimerized high-affinity mature 67-kDa mLRP that may act as a cofactor to stabilize the binding of laminin to cell surface integrins, and the 37-kDa OFA-iLRP, which is not expressed by adult differentiated tissues⁵. The immunotherapeutic potential of OFA-iLRP has been recently proposed, as HLA-A2 specific CD8⁺ cells, generated from the peripheral blood of healthy donors or cancer patients, lysed OFA-iLRP⁺ acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL) cells^(6;7).

Unlike Id, OFA-iLRP is highly evolutionary conserved antigen that contains number of CD8⁺ T cell epitopes expressed by human cancer cells⁷. Accordingly, a need exists for the development of anti-cancer vaccines that are not individually tailored and have broad ability to treat and prevent cancer, and OFA-iLRP may be useful if it can be made antigenic.

SUMMARY OF THE INVENTION

The inventors of the instant application have developed a novel strategy for rendering weakly or non-immunogenic self tumor antigens immunogenic. The strategy is based on use of proinflammatory chemokines to deliver antigens to immature DCs through targeting chemokine receptors differentially expressed on APCs^(1;2). Using the technology described herein, protein or DNA immunizations elicit therapeutic antitumor immunity against wide variety of tumors, which express non-immunogenic or weakly immunogenic tumor antigens, such as, for example, the embryonic antigen OFA.

Accordingly, the instant invention is based, at least in part, on the discovery that tumor-associated embryonic antigens, e.g., OFA-iLRP, though non-antigenic alone, are effective for the treatment and/or prevention of cancer when linked to a chemoattractant ligand, e.g., a proinflammatory chemokine such as MIP3α/CCL20 or β-defensin mDF2β. Accordingly, the instant invention provides methods and compositions for the treatment and prevention of cell proliferative disorders, e.g., cancer, using the discovered molecules.

In one aspect, the invention provides nucleic acid molecules encoding a tumor-associated embryonic antigen and a chemoattractant ligand. In one embodiment, the tumor-associated embryonic antigen is human or mouse OFA-iLRP. In another embodiment, the chemoattractant ligand is specific for CCR6, e.g., MIP3α/CCL20 or β-defensin DF2β. In particular embodiments, the chemoattractant ligand is human or murine. In another embodiment, the chemoattractant ligand is murine or human EP2C, murine or human β-defensin 1 (MBD1), or a C-terminal fragment of mycobacterial HSP 70.

In a specific embodiment, the invention provides nucleic acid molecules encoding β-defensin DF2β and OFA-iLRP, or functional fragments thereof. In another specific embodiment, the β-defensin DF2β is human β-defensin DF2β. In yet another specific embodiment, the β-defensin DF2β is murine β-defensin DF2β. The sequence of one exemplary nucleic acid molecule encoding β-defensin DF2β and OFA-iLRP is set forth as SEQ ID NO: 1.

In another specific embodiment, the invention provides nucleic acid molecules encoding MIP3α/CCL20 and OFA-iLRP, or functional fragments thereof. In one specific embodiment, the MIP3α/CCL20 is human MIP3α/CCL20. In yet another specific embodiment, the MIP3α/CCL20 is murine MIP3α/CCL20. The sequence of one exemplary nucleic acid molecule encoding MIP3α/CCL20 and OFA-iLRP is set forth as SEQ ID NO:3.

In another specific embodiment, the invention provides nucleic acid molecules encoding EP2C and OFA-iLRP, or functional fragments thereof. In one specific embodiment, the EP2C is human EP2C. In yet another specific embodiment, the EP2C is murine EP2C. The sequence of one exemplary nucleic acid molecule encoding EP2C and OFA-iLRP is set forth as SEQ ID NO: 5.

In another specific embodiment, the invention provides nucleic acid molecules encoding the C-terminal fragment of mycobacterial HSP 70 and OFA-iLRP, or functional fragments thereof. The sequence of one exemplary nucleic acid molecule encoding C-terminal fragment of mycobacterial HSP 70 and OFA-iLRP is set forth as SEQ ID NO: 7.

In specific embodiments, the OFA-iLRP is murine OFA-iLRP. In other specific embodiments, the OFA-iLRP is human OFA-iLRP.

In another embodiment, the invention provides nucleic acid molecules encoding a linker polypeptide between the tumor-associated embryonic antigen and the chemoattractant ligand. In another aspect, the embodiment, the invention provides nucleic acid molecules encoding a purification tag, e.g., a myc or his tag. In yet another embodiment, the invention provides nucleic acid molecules described herein further encoding a signal sequence, e.g., the IP 10 signal sequence.

In another aspect, the invention provides vectors comprising the nucleic acid molecules described herein.

In another aspect, the invention provides the nucleic acid molecules described herein for the treatment or prevention of cancer, e.g., hematological, breast, renal, lung or ovarian cancer.

In another aspect, the invention provides polypeptides comprising a tumor-associated embryonic antigen and a chemoattractant ligand. In one embodiment, the tumor-associated embryonic antigen is OFA-iLRP. In another embodiment, the chemoattractant ligand is specific for CCR6, e.g., MIP3α/CCL20 or β-defensin mDF2β. In one embodiment, the MIP3α/CCL20 or β-defensin DF2β is human or murine MIP3α/CCL20 or β-defensin DF2β.

In one embodiment, the chemoattractant ligand is murine or human EP2C, human β-defensin 1 (hBD1), or a C-terminal fragment of mycobacterial HSP 70.

In another embodiment, the invention provides polypeptides comprising β-defensin DF2β and OFA-iLRP, or functional fragments thereof. In a related embodiment, the β-defensin DF2β is human β-defensin DF2β. In another related embodiment, the β-defensin DF2β is murine β-defensin DF2β. The sequence of one exemplary polypeptide comprising β-defensin DF2β and OFA-iLRP is set forth as SEQ ID NO: 2.

In another embodiment, the invention provides polypeptides comprising MIP3α/CCL20 and OFA-iLRP, or functional fragments thereof. In a related embodiment, the MIP3α/CCL20 is human MIP3α/CCL20. In another related embodiment, the MIP3α/CCL20β is murine MIP3α/CCL20β. The sequence of one exemplary polypeptide comprising MIP3α/CCL20 and OFA-iLRP is set forth as SEQ ID NO:4.

In another embodiment, the invention provides polypeptides comprising EP2C and OFA-iLRP, or functional fragments thereof. In a related embodiment, the EP2C is human EP2C. In another related embodiment, the EP2C is murine EP2C. The sequence of one exemplary polypeptide comprising EP2C and OFA-iLRP is set forth as SEQ ID NO: 6.

In another embodiment, the invention provides polypeptides comprising a C-terminal fragment of mycobacterial HSP 70 and OFA-iLRP, or functional fragments thereof. The sequence of one exemplary polypeptide comprising a C-terminal fragment of mycobacterial HSP 70 and OFA-iLRP is set forth as SEQ ID NO: 8.

In certain embodiments, the OFA-iLRP is human OFA-iLRP. In other embodiments, the OFA-iLRP is murine OFA-iLRP.

In another embodiment, the invention provides polypeptides comprising a tumor-associated embryonic antigen and a chemoattractant ligand and further comprising a polypeptide linker between the tumor-associated embryonic antigen and the chemoattractant ligand.

In another embodiment, the invention provides polypeptides comprising a tumor-associated embryonic antigen and a chemoattractant ligand and further comprising a purification tag, e.g., a myc or his tag.

In another aspect, the instant invention provides a cancer vaccine comprising the nucleic acid molecules described herein and an adjuvant. In another aspect, the instant invention provides a cancer vaccine comprising one or more of the polypeptides described herein.

In another aspect, the instant invention also provides methods of treating a subject having cancer by administering to the subject a nucleic acid molecule or polypeptide as described herein, thereby treating the subject. In exemplary embodiments, the cancer is breast, renal, lung, ovarian or a hematological cancer.

In another aspect, the invention provides methods of immunizing a subject against cancer by administering to the subject a nucleic acid molecule, polypeptide or vaccine as described herein, thereby immunizing the subject.

The invention also provides a kit comprising a vaccine as described herein and instructions for use.

The invention also provides a kit comprising a nucleic acid as described herein and instructions for use.

The invention also provides a kit comprising a polypeptide as described herein and instructions for use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-B depict genetic immunizations with constructs expressing mDF2β fusions with non-immunogenic TAAs induce protective anti-lymphoma (A). BALB/c mice (ten per group), immunized with pmDF2β-OFA (closed circle) or pmDF2β-sFv20 (open triangle), were challenged i.p. with 2.5×10⁵ A20 lymphoma cells. A separate group of mice were injected with a mixture of pmDF2β-sFv20 and pMIP3α-OFA (closed square) or mock with PBS (open diamond). Logrank P-value is for comparison between pmDF2β-OFA or pmDF2β-sFv20 and PBS. A representative experiment of at least three independent experiments is shown, all yielding similar results. (B) Mice immunized with pmDF2β-OFA generate significant OFA-specific IgG1 (open triangle) and IgG2a (closed triangle). Shown is representative plot of experiments of sera mixed five 5 mice per group. No OFA specific antibody was detected in sera of mock immunized mice (open circle, IgG1, and closed circle, IgG2a). Titrated amounts of immune or naïve mouse sera were incubated for 1 hour on the same plate coated with 3 μg/ml of recombinant TARC-OFA, and the Ig isotypes were determined using goat anti-mouse IgG1- or IgG2a-HRP antibodies (Caltag).

FIGS. 2A-B demonstrate that vaccine induces a T cell response. (A) Splenocytes from mice immunized with pMIP3α-OFA or with the iLR₅₈₋₆₆ peptide/IFA specifically lyse A20 lymphoma cells (pMIP3α-OFA/A20 and OFA peptide/A20), but not HLA-matched (H-2K^(d)) but OFA⁻ MOPC315 (pMIP3α-OFA/MOPC315 and OFA peptide/MOPC315, or mismatched (H-2^(b)) EL-4 (pMIP3α-OFA and OFA peptide/EL4) tumor cells. Control splenocytes from mice injected with PBS or immunized with OFA fusions with a mutant MIP3α (pMIP3α-D-OFA), which could not bind CCR6, failed to lyse either of cells. Shown here is percentage of cytotoxicity (Y-axis) of two representative and independent experiments with similar results, performed in triplicates. X-axis is effector:target ratio (E:T) of cells used. (B) Tumor protection requires presence of the OFA-specific effector CD8⁺ T cells. Mice were immunized with pMIP3α-OFA plasmid as above and randomly allocated (ten per group) to treatment with anti-CD8 mAb GK2.43, anti-CD4 mAb GK1.5, or normal rat IgG. P-values refer to comparison between anti-CD8 mAb and IgG injected groups. Flow cytometry analysis of splenocytes from normal mice treated with these mAb in parallel one and two weeks after treatment confirmed a >90% depletion of the appropriate subset with normal levels of the other subset (data not shown).

FIGS. 3A-C. (A) Chemoattractants facilitate the CCR6-mediated uptake, processing and presentation of OFA to MHC Class I molecules. Naïve BALB/C mouse iDCs (target cells) were incubated overnight with 100 ng/ml MIP3α-OFA or mDF2β-OFA. Then, after extensive washings and irradiation, they were co-cultured with immune effector splenocytes from BALB/C mice (immunized with the iLR₅₈₋₆₆ peptide/IFA) and IFN-γ release was measured after overnight incubation. Effector cell specificity was validated using splenocytes pulsed with 1 μg/ml of the iLR₅₈₋₆₆ (OFA peptide) or MOPC315 peptides (irrelevant peptide); or incubating with OFA⁺ A20 lymphoma or OFA⁻ MOPC315 tumor cells. Control DCs treated with MIP3α fused with an irrelevant tumor antigen or MC148-D-mOFA (data not shown) or mixture of untreated effector cells with splenocytes (E+T) failed to stimulate T cells. Some iDC were also treated in presence of 0.4 M sucrose, or pertussis toxin (PTX), or chloroquine, or brefeldin A, or lactacystin. P-values refer to comparisons after treatment with chlroquine. (B) Co-localization study. To enable internalization, the pre-chilled on ice cells were placed at 37° C. for the time indicated by the column headings. Green, MIP3α-fusions stained with anti-myc mAb 1.9 μg/mL and goat anti-mouse Alexa 488 2 μg/mL. Red fluorophore, Alexa 568 conjugated to goat anti-rabbit IgG, specific for either clathrin (top raw), LAMP (middle row) and proteasomes (bottom row). Merged signal is yellow. Transmission light image is of the 0 min time cell. Scale bar is 5 μm (white rectangle). (C) Processed OFA is presented on MHC class I molecules. iDCs were incubated with mDF2β-OFA or MIP3α-OFA in presence of neutralizing anti-MHC class I (H-2^(d)) or isotype-matched control antibodies. Same treatment was performed for control iDCs incubated with 1 μg/ml the OFA or MOPC315 peptides. P-values refer to comparisons with control Abs. Shown, representative data of at least two (C) and three (A and B) independent experiments yielding similar results.

FIG. 4 depicts treatment with pMIP3α-OFA eradicates established A20 lymphoma. BALB/c mice (ten mice per group) bearing A20 lymphoma were treated immunizing with pMIP3α-OFA or pHsp70-OFA. Control mice were mock treated with PBS or electroporated with pMIP3α-D-OFA. Tumor free survival was followed for 100 days post tumor challenge. The data shown is representative of four independent experiments which yielded similar results. P-value refers to comparison with pMIP3α-D-OFA.

FIG. 5 demonstrates that chemokine or defense fusion proteins are taken up, processed and presented by APCs in vitro via chemokine receptor utilizing MHC class II pathway. Titrated amounts of protein (shown in ng/ml), 91-101 peptide or an irrelevant peptide derived from A20 lymphoma VL chain were incubated with BALB/c mice immature DCs. APCs were then washed, irradiated and placed in culture with epitope-specific 7A10B2 T cell line for 48 hrs, and IFNγ was assayed in culture supernatants. Control treatment groups were immature DCs or matured by overnight treatment with LPS (10 ng/ml) DCs were pulsed with 0.2 μg/ml 91-101 peptide, or with 10 μg/ml irrelevant peptide.

FIGS. 6A-B demonstrate that chemokine fusion enables tumor antigens to be efficiently cross-presented, i.e. processed and presented to MHC class I. The intracellular trafficking of Chemokine receptors is dependent on clathrin-associated vesicles (since inhibited with sucrose) and G-protein signaling (inhibited with peruses toxin, PTX) (A). Specificity of effector cells was tested on iDC pulsed with hgp100₂₅₋₃₃ peptide, or control A20 peptide, or mixing with cells such as B16 melanoma (H-2^(b)), EL4 (H-2^(b)), and A20 (H-2^(d)). iDC were treated with 0.1 μg/ml chemokine proteins fused with gp100 in the presence or absence of various pharmacological inhibitors (μM) of intracellular organelle trafficking, such as leupeptin and chloroquine (for endosomal-lysosomal), or brefeldin A (vesicle transport between the ER and Golgi). Titrated doses of lactacystin (a specific proteasomal inhibitor, shown in μM), a used to test for cytosolic processing (B).

FIG. 7 demonstrates that cross-presentation of chemokine fusion vaccines requires TAP-1 machinery. Immature DC derived from TAP-1 knockout (TAP KO) or wild type C57BL/6 mice were incubated with 0.1 μg/ml either MIP3α-gp100 or the gp100 protein alone and tested for their ability to stimulate gp 100-specific T cells derived from pmel-1 mice, as described. Control APC were treated with the active gp 100 peptide, hgp100₂₅₋₃₃, or irrelevant A20 peptides. IFN-γ release was measured in the supematants of cells cultured for 24 hours by ELISA.

FIG. 8 demonstrates that chemokine fusion vaccination elicits protective anti-tumor responses in C57BL/6 mice. Ten mice per group were gene-gun immunized three times with pMIP3α-gp100, pMIP3α-D-gp100 (a fusion with a mutated MIP3α which can not bind to CCR6) or PBS. Two weeks after the last immunization, mice were challenged s.c. with a lethal dose of B16 tumor cells. Tumor growth suppression was subsequently assessed and mice with tumor greater than 400 mm² were euthanized. The data shown is representative of two independent experiments which yielded similar results. P-value is 0.02.

FIG. 9 demonstrates that tumor protection requires secretion of chemotactic fusion protein

FIGS. 10A-10B demonstrate that antibody responses to the same antigen depend on a type of chemokine used. Mice were gene gun immunized with DNA constructs expressing non-immunogenic tumor antigen (sFv38) fused with various chemokines.

FIGS. 11A-B demonstrate that immunizations with viral chemokine carriers induce antitumor protection. Ten per group C3H mice were gene gun with plasmids indicated immunized three times in every two weeks, and two after, mice were i.p. challenged with 10× lethal dose (3000 cells) of 38C13.

FIGS. 12A-B depict the results of experiments demonstrating CCR6 vs. CCR7: MIP3α fusion constructs elicit antitumor protection, although both SLC and MIP3α fusions generate anti-Id Abs.

FIG. 13 demonstrates that injection of plasmid DNA encoding iDC chemo-attractant fusions elicit therapeutic antitumor immunity.

FIGS. 14.1-14.18 depict SEQ ID NOs: 1-30.

FIGS. 15A-D depict eradication of A20 lymphoma promote long-term T cell-mediated memory that protects mice from re-challenge with A20 lymphoma. (A) sixteen mice that were free of tumors for about 9 months (open circles) and control ten age-matched naïve BALB/C mice (closed circles) were challenged with A20 lymphoma cells. P-value refers to comparison with control mice. (B) In parallel, splenocytes of long-term survivor mice (E, effector cells) were in vitro stimulated for one week on DCs pused with OFA-peptide and tested against target cells (T), such as A20, 4T 1, and B 16 tumors, at indicated ration (T:E). Shown, percentage of cytotoxicity (Y-axis) of a representative experiment performed in triplicate. (C) OFA-iLRP is expressed on the surface of A20 lymphoma and B16 melanoma cells, but not 4T1 tumor cells. OFA expression was determined with Alexa-488-conjugated anti-OFA mAB (bold lines) vs. control Alexa-488-conjugated isotype-matched AB. (D) Mice that survived A20 tumor challenge (A20-survivor+4T1, see also A) or control BALB/c mice (HBs+4T1) immunized with control constructs expressing HbsAg were re-challenged with 4T1 tumor cells.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention is based, at least in part, on the discovery that non-immunogenic tumor antigens, e.g., OFA-iLRP, can be rendered immunogenic by using a chemoattractant ligand, e.g., a proinflammatory chemokine. In a preferred embodiment, the tumor antigen and chemoattractant ligand are expressed as a fusion polypeptide or are encoded by a single nucleic acid molecule. These molecules are useful in the prevention and treatment of cell proliferative disorders, e.g., cancer. Accordingly, the instant invention provides polypeptides, nucleic acid molecules, vectors, host cells, vaccines, kits and methods of treating or preventing cancer.

Molecules of the Invention

The present invention provides fusion molecules, e.g., molecules comprising a tumor antigen and chemoattractant ligand. The tumor antigen and chemoattractant ligand are optionally attached by a linker, e.g., a peptide or non-peptide linker. The invention provides polypeptides comprising a tumor antigen and chemoattractant ligand and nucleic acid molecules encoding a tumor antigen and chemoattractant ligand. In certain embodiments, the molecules comprise fragments of the tumor antigen and/or the chemoattractant ligand, wherein the fragments are effective to achieve the desired biological effect.

Exemplary tumor antigen are those that are expressed in embryonic tissue but not in mature tissue. An exemplary tumor antigen useful in the methods and compositions of the invention is the 37 kD oncofetal Ag-immature laminin receptor (OFA-iLRP) (SEQ ID NO:31).

Exemplary chemoattractant ligands include proinflammitory chemokines. Specific exemplary chemoattractant ligands include chemoattractant ligands specific for CCR6, e.g., MIP3α/CCL20 or β-defensin DF2β. Further chemoattractant ligands include EP2C, β-defensin 1 (MBD1), or a C-terminal fragment of mycobacterial HSP 70. For all chemoattractant ligands other than mycobacterial HSP 70, the chemoattractant can be human or murine. The sequence of all the exemplary chemoattractant ligands set forth herein are set forth in the sequence of the exemplary polypeptides and nucleic acid molecules set forth herein.

One of skill in the art can identify chemoattractant ligands and understands that homologues and orthologues of these molecules will be useful in the methods and compositions of the instant invention. Moreover, variants and biologically active fragments of these ligands are useful in the methods of the invention.

The polypeptides of the invention may be assembled post-translationally, i.e., the tumor antigen and chemoattractant ligand can be covalently linked after being synthesized, or expressed, separately. Alternatively, the tumor antigen and chemoattractant ligand can be expressed recombinantly as one polypeptide.

The polypeptides of the invention may further comprise a polypeptide linker located between the tumor antigen and chemoattractant ligand. The polypeptides of the invention may further comprise one or more purification tags, e.g., a myc or histidine tag. Finally, the polypeptides of the invention may comprise a signal sequence to direct the location of the polypeptide.

The invention also provides nucleic acid molecules encoding a tumor antigen and chemoattractant ligand such as those described herein. Moreover, the nucleic acid molecules may further encode a polypeptide linker located between the tumor antigen and chemoattractant ligand. The nucleic acid molecules of the invention may further encode a signal sequence to direct the location of the polypeptide. The nucleic acid molecules of the invention may further encode a purification tag, e.g., a myc or histidine tag.

The invention also provides vectors, e.g., expression vectors, containing a nucleic acid molecule of the invention. As used herein, the term “vector” refers to a nucleic acid molecule capable of transporting another nucleic acid molecule to which it has been linked. One type of vector is a “plasmid”, which refers to a circular double stranded DNA loop into which additional DNA segments can be ligated. Another type of vector is a viral vector, wherein additional DNA segments can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “expression vectors”. In general, expression vectors are often in the form of plasmids. In the present specification, “plasmid” and “vector” can be used interchangeably as the plasmid is the most commonly used form of vector. However, the invention is intended to include such other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions.

The recombinant expression vectors of the invention comprise a nucleic acid molecule of the invention in a form suitable for expression of the nucleic acid molecule in a host cell, which means that the recombinant expression vectors include one or more regulatory sequences, selected on the basis of the host cells to be used for expression, which is operatively linked to the nucleic acid sequence to be expressed. Within a recombinant expression vector, “operably linked” is intended to mean that the nucleotide sequence of interest is linked to the regulatory sequence(s) in a manner which allows for expression of the nucleotide sequence (e.g., in an in vitro transcription/translation system or in a host cell when the vector is introduced into the host cell). The term “regulatory sequence” is intended to include promoters, enhancers and other expression control elements (e.g., polyadenylation signals). Such regulatory sequences are described, for example, in Goeddel; Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990). Regulatory sequences include those which direct constitutive expression of a nucleotide sequence in many types of host cells and those which direct expression of the nucleotide sequence only in certain host cells (e.g., tissue-specific regulatory sequences). It will be appreciated by those skilled in the art that the design of the expression vector can depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, and the like. The expression vectors of the invention can be introduced into host cells to thereby produce proteins or peptides, including fusion proteins or peptides, encoded by nucleic acids as described herein (e.g., fusion molecules comprising a chemokine receptor ligand and a toxin moiety).

The recombinant expression vectors of the invention can be designed for expression of the polypeptides of the invention in prokaryotic or eukaryotic cells. For example, the polypeptides can be expressed in bacterial cells such as E. coli, insect cells (using baculovirus expression vectors) yeast cells or mammalian cells. Suitable host cells are discussed further in Goeddel, Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990). Alternatively, the recombinant expression vector can be transcribed and translated in vitro, for example using T7 promoter regulatory sequences and T7 polymerase.

Expression of proteins in prokaryotes is most often carried out in E. coli with vectors containing constitutive or inducible promoters directing the expression of either fusion or non-fusion proteins. Fusion vectors add a number of amino acids to a protein encoded therein, usually to the amino terminus of the recombinant protein. Such fusion vectors typically serve three purposes: 1) to increase expression of recombinant protein; 2) to increase the solubility of the recombinant protein; and 3) to aid in the purification of the recombinant protein by acting as a ligand in affinity purification. Often, in fusion expression vectors, a proteolytic cleavage site is introduced at the junction of the fusion moiety and the recombinant protein to enable separation of the recombinant protein from the fusion moiety subsequent to purification of the fusion protein. Such enzymes, and their cognate recognition sequences, include Factor Xa, thrombin and enterokinase. Typical fusion expression vectors include pGEX (Pharmacia Biotech Inc; Smith, D. B. and Johnson, K. S. (1988) Gene 67:31-40), pMAL (New England Biolabs, Beverly, Mass.) and pRIT5 (Pharmacia, Piscataway, N.J.) which fuse glutathione S-transferase (GST), maltose E binding protein, or protein A, respectively, to the target recombinant protein.

Examples of suitable inducible non-fusion E. coli expression vectors include pTrc (Amann et al., (1988) Gene 69:301-315) and pET 11d (Studier et a, Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990) 60-89). Target gene expression from the pTrc vector relies on host RNA polymerase transcription from a hybrid trp-lac fusion promoter. Target gene expression from the pET 11d vector relies on transcription from a T7 gn10-lac fusion promoter mediated by a coexpressed viral RNA polymerase (T7 gn1). This viral polymerase is supplied by host strains BL21(DE3) or HMS174(DE3) from a resident prophage harboring a T7 gn1 gene under the transcriptional control of the lacUV 5 promoter.

One strategy to maximize recombinant protein expression in E. coli is to express the protein in a host bacteria with an impaired capacity to proteolytically cleave the recombinant protein (Gottesman, S., Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990) 119-128). Another strategy is to alter the nucleic acid sequence of the nucleic acid to be inserted into an expression vector so that the individual codons for each amino acid are those preferentially utilized in E. coli (Wada et al., (1992) Nucleic Acids Res. 20:2111-2118). Such alteration of nucleic acid sequences of the invention can be carried out by standard DNA synthesis techniques.

In another embodiment, the expression vector is a yeast expression vector. Examples of vectors for expression in yeast S. cerivisae include pYepSec1 (Baldari, et al., (1987) EMBO J 6:229-234), pMFa (Kudjan and Herskowitz, (1982) Cell 30:933-943), pJRY88 (Schultz et al., (1987) Gene 54:113-123), pYES2 (Invitrogen Corporation, San Diego, Calif.), and picZ (InVitrogen Corp, San Diego, Calif.).

Alternatively, the nucleic acid molecules of the invention may be used to express polypeptides in insect cells using baculovirus expression vectors. Baculovirus vectors available for expression of proteins in cultured insect cells (e.g., Sf9 cells) include the pAc series (Smith et al. (1983) Mol. Cell Biol. 3:2156-2165) and the pVL series (Lucklow and Summers (1989) Virology 170:31-39).

In yet another embodiment, a nucleic acid of the invention is expressed in mammalian cells using a mammalian expression vector. Examples of mammalian expression vectors include pCDM8 (Seed, B. (1987) Nature 329:840) and pMT2PC (Kaufman et al. (1987) EMBO J 6:187-195). When used in mammalian cells, the expression vector's control functions are often provided by viral regulatory elements. For example, commonly used promoters are derived from polyoma, Adenovirus 2, cytomegalovirus and Simian Virus 40. For other suitable expression systems for both prokaryotic and eukaryotic cells see chapters 16 and 17 of Sambrook, J., Fritsh, E. F., and Maniatis, T. Molecular Cloning: A Laboratory Manual. 2nd, ed., Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989.

In another embodiment, the recombinant mammalian expression vector is capable of directing expression of the nucleic acid preferentially in a particular cell type (e.g., tissue-specific regulatory elements are used to express the nucleic acid). Tissue-specific regulatory elements are known in the art. Non-limiting examples of suitable tissue-specific promoters include the albumin promoter (liver-specific; Pinkert et al. (1987) Genes Dev. 1:268-277), lymphoid-specific promoters (Calame and Eaton (1988) Adv. Immunol. 43:235-275), in particular promoters of T cell receptors (Winoto and Baltimore (1989) EMBO J 8:729-733) and immunoglobulins (Banedji et al. (1983) Cell 33:729-740; Queen and Baltimore (1983) Cell 33:741-748), neuron-specific promoters (e.g., the neurofilament promoter; Byrne and Ruddle (1989) Proc. Natl. Acad. Sci. USA 86:5473-5477), pancreas-specific promoters (Edlund et al. (1985) Science 230:912-916), and mammary gland-specific promoters (e.g., milk whey promoter; U.S. Pat. No. 4,873,316 and European Application Publication No. 264,166). Developmentally-regulated promoters are also encompassed, for example the murine hox promoters (Kessel and Gruss (1990) Science 249:374-379) and the α-fetoprotein promoter (Campes and Tilghman (1989) Genes Dev. 3:537-546).

Another aspect of the invention pertains to host cells into which a nucleic acid molecule encoding a polypeptide of the invention is introduced within a recombinant expression vector or a nucleic acid molecule containing sequences which allow it to homologously recombine into a specific site of the host cell's genome. The terms “host cell” and “recombinant host cell” are used interchangeably herein. It is understood that such terms refer not only to the particular subject cell but to the progeny or potential progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term as used herein.

A host cell can be any prokaryotic or eukaryotic cell. For example, a polypeptide of the invention can be expressed in bacterial cells such as E. coli, insect cells, yeast or mammalian cells (such as Chinese hamster ovary cells (CHO) or COS cells). Other suitable host cells are known to those skilled in the art.

Vector DNA can be introduced into prokaryotic or eukaryotic cells via conventional transformation or transfection techniques. As used herein, the terms “transformation” and “transfection” are intended to refer to a variety of art-recognized techniques for introducing foreign nucleic acid (e.g., DNA) into a host cell, including calcium phosphate or calcium chloride co-precipitation, DEAF-dextran-mediated transfection, lipofection, or electroporation. Suitable methods for transforming or transfecting host cells can be found in Sambrook, et al. (Molecular Cloning: A Laboratory Manual. 2nd, ed., Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989), and other laboratory manuals.

For stable transfection of mammalian cells, it is known that, depending upon the expression vector and transfection technique used, only a small fraction of cells may integrate the foreign DNA into their genome. In order to identify and select these integrants, a gene that encodes a selectable marker (e.g., resistance to antibiotics) is generally introduced into the host cells along with the gene of interest. Preferred selectable markers include those which confer resistance to drugs, such as G418, hygromycin and methotrexate. Nucleic acid encoding a selectable marker can be introduced into a host cell on the same vector as that encoding the polypeptide of the invention or can be introduced on a separate vector. Cells stably transfected with the introduced nucleic acid can be identified by drug selection (e.g., cells that have incorporated the selectable marker gene will survive, while the other cells die).

A host cell of the invention, such as a prokaryotic or eukaryotic host cell in culture, can be used to produce (i.e., express) the polypeptides of the invention. Accordingly, the invention further provides methods for producing polypeptides using the host cells of the invention. In one embodiment, the method comprises culturing the host cell of the invention (into which a recombinant expression vector encoding a polypeptide of the invention has been introduced) in a suitable medium such that a polypeptides of the invention is produced. In another embodiment, the method further comprises isolating the polypeptide from the medium or the host cell.

The host cells of the invention can also be used to produce non-human transgenic animals. For example, in one embodiment, a host cell of the invention is a fertilized oocyte or an embryonic stem cell into which coding sequences have been introduced. Such host cells can then be used to create non-human transgenic animals in which exogenous sequences have been introduced into their genome or homologous recombinant animals in which endogenous sequences have been altered. As used herein, a “transgenic animal” is a non-human animal, preferably a mammal, more preferably a rodent such as a rat or mouse, in which one or more of the cells of the animal includes a transgene. Other examples of transgenic animals include non-human primates, sheep, dogs, cows, goats, chickens, amphibians, and the like.

Methods of Making the Molecules of the Invention

As described above, molecules of the invention may be made recombinantly using the nucleic acid molecules, vectors, and host cells described above.

Alternatively, the tumor antigen and chemoattractant ligand can be made synthetically, or isolated from a natural source and linked together using methods and techniques well known to one of skill in the art.

Further, to increase the stability or half life of the fusion molecules of the invention, the peptides may be made, e.g., synthetically or recombinantly, to include one or more peptide analogs or mimmetics. Exemplary peptides can be synthesized to include D-isomers of the naturally occurring amino acid residues to increase the half life of the molecule when administered to a subject.

Pharmaceutical Compositions

The nucleic acid and polypeptide fusion molecules (also referred to herein as “active compounds”) of the invention can be incorporated into pharmaceutical compositions. Such compositions typically include the nucleic acid molecule or protein, and a pharmaceutically acceptable carrier. As used herein the language “pharmaceutically acceptable carrier” includes solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like, compatible with pharmaceutical administration. Supplementary active compounds can also be incorporated into the compositions.

Pharmaceutical compositions of the instant invention may also include one or more other active compounds. Alternatively, the pharmaceutical compositions of the invention may be administered with one or more other active compounds. Other active compounds that can be administered with the pharmaceutical compounds of the invention, or formulated into the pharmaceutical compositions of the invention, include, for example, anticancer compounds.

A pharmaceutical composition is formulated to be compatible with its intended route of administration. Examples of routes of administration include parenteral, e.g., intravenous, intradermal, subcutaneous, oral (e.g., inhalation), transdermal (topical), transmucosal, and rectal administration. Solutions or suspensions used for parenteral, intradermal, or subcutaneous application can include the following components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic.

Preferred pharmaceutical compositions of the invention are those that allow for local delivery of the active ingredient, e.g., delivery directly to the location of a tumor.

Pharmaceutical compositions suitable for injectable use include sterile aqueous solutions (where water soluble) or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersion. For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor EL™. (BASF, Parsippany, N.J.) or phosphate buffered saline (PBS). In all cases, the composition must be sterile and should be fluid to the extent that easy syringability exists. It should be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyetheylene glycol, and the like), and suitable mixtures thereof. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prevention of the action of microorganisms can be achieved by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols such as manitol, sorbitol, sodium chloride in the composition. Prolonged absorption of the injectable compositions can be brought about by including in the composition an agent which delays absorption, for example, aluminum monostearate and gelatin.

Sterile injectable solutions can be prepared by incorporating the active compound in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the active compound into a sterile vehicle which contains a basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze-drying which yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof.

Oral compositions generally include an inert diluent or an edible carrier. For the purpose of oral therapeutic administration, the active compound can be incorporated with excipients and used in the form of tablets, troches, or capsules, e.g., gelatin capsules. Oral compositions can also be prepared using a fluid carrier for use as a mouthwash. Pharmaceutically compatible binding agents, and/or adjuvant materials can be included as part of the composition. The tablets, pills, capsules, troches and the like can contain any of the following ingredients, or compounds of a similar nature: a binder such as microcrystalline cellulose, gum tragacanth or gelatin; an excipient such as starch or lactose, a disintegrating agent such as alginic acid, Primogel, or corn starch; a lubricant such as magnesium stearate or Sterotes; a glidant such as colloidal silicon dioxide; a sweetening agent such as sucrose or saccharin; or a flavoring agent such as peppermint, methyl salicylate, or orange flavoring.

For administration by inhalation, the compounds are delivered in the form of an aerosol spray from pressured container or dispenser which contains a suitable propellant, e.g., a gas such as carbon dioxide, or a nebulizer.

Systemic administration can also be by transmucosal or transdermal means. For transmucosal or transdermal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art, and include, for example, for transmucosal administration, detergents, bile salts, and fusidic acid derivatives. Transmucosal administration can be accomplished through the use of nasal sprays or suppositories. For transdermal administration, the active compounds are formulated into ointments, salves, gels, or creams as generally known in the art.

The compounds can also be prepared in the form of suppositories (e.g., with conventional suppository bases such as cocoa butter and other glycerides) or retention enemas for rectal delivery.

In one embodiment, the active compounds are prepared with carriers that will protect the compound against rapid elimination from the body, such as a controlled release formulation, including implants and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Methods for preparation of such formulations will be apparent to those skilled in the art. The materials can also be obtained commercially from Alza Corporation and Nova Pharmaceuticals, Inc. Liposomal suspensions (including liposomes targeted to infected cells with monoclonal antibodies to viral antigens) can also be used as pharmaceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art, for example, as described in U.S. Pat. No. 4,522,811.

It is advantageous to formulate oral or parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the subject to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier.

Toxicity and therapeutic efficacy of such compounds can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., for determining the LD50 (the dose lethal to 50% of the population) and the ED50 (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index and it can be expressed as the ratio LD50/ED50. Compounds which exhibit high therapeutic indices are preferred. While compounds that exhibit toxic side effects can be used, care should be taken to design a delivery system that targets such compounds to the site of affected tissue in order to minimize potential damage to uninfected cells and, thereby, reduce side effects.

The data obtained from the cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage of such compounds lies preferably within a range of circulating concentrations that include the ED50 with little or no toxicity. The dosage can vary within this range depending upon the dosage form employed and the route of administration utilized. For any compound used in the method of the invention, the therapeutically effective dose can be estimated initially from cell culture assays. A dose can be formulated in animal models to achieve a circulating plasma concentration range that includes the IC50 (i.e., the concentration of the test compound which achieves a half-maximal inhibition of symptoms) as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Levels in plasma can be measured, for example, by high performance liquid chromatography.

As defined herein, a therapeutically effective amount of protein or polypeptide (i.e., an effective dosage) ranges from about 0.001 to 30 mg/kg body weight, preferably about 0.01 to 25 mg/kg body weight, more preferably about 0.1 to 20 mg/kg body weight, and even more preferably about 1 to 10 mg/kg, 2 to 9 mg/kg, 3 to 8 mg/kg, 4 to 7 mg/kg, or 5 to 6 mg/kg body weight. The protein or polypeptide can be administered one time per week for between about 1 to 10 weeks, preferably between 2 to 8 weeks, more preferably between about 3 to 7 weeks, and even more preferably for about 4, 5, or 6 weeks. The skilled artisan will appreciate that certain factors can influence the dosage and timing required to effectively treat a subject, including but not limited to the severity of the disease or disorder, previous treatments, the general health and/or age of the subject, and other diseases present. Moreover, treatment of a subject with a therapeutically effective amount of a polypeptide or nucleic acid molecule can include a single treatment or, preferably, can include a series of treatments.

The nucleic acid molecules of the invention can be inserted into vectors and used as gene therapy vectors. Gene therapy vectors can be delivered to a subject by, for example, intravenous injection, local administration (see U.S. Pat. No. 5,328,470) or by stereotactic injection (see e.g., Chen et al. (1994) Proc. Natl. Acad. Sci. USA 91:3054-3057). The pharmaceutical preparation of the gene therapy vector can include the gene therapy vector in an acceptable diluent, or can comprise a slow release matrix in which the gene delivery vehicle is imbedded. Alternatively, where the complete gene delivery vector can be produced intact from recombinant cells, e.g., retroviral vectors, the pharmaceutical preparation can include one or more cells which produce the gene delivery system.

The pharmaceutical compositions can be included in a container, pack, kit or dispenser together with instructions, e.g., written instructions, for administration, particularly such instructions for use of the active agent to treat against a disorder or disease as disclosed herein, including an autoimmune disease or disorder, treatment in connection with an organ or tissue transplant, as well as other diseases or disorders with an autoimmune component such as AIDS. The container, pack, kit or dispenser may also contain, for example, a fusion molecule, a nucleic acid sequence encoding a fusion molecule, or a fusion molecule expressing cell.

Methods of Treatment

The compositions disclosed herein may be useful in the treatment or prevention of cancer.

The term “cancer” includes malignancies characterized by deregulated or uncontrolled cell growth, for instance carcinomas, sarcomas, leukemias, and lymphomas. The term “cancer” includes primary malignant tumors, e.g., those whose cells have not migrated to sites in the subject's body other than the site of the original tumor, and secondary malignant tumors, e.g., those arising from metastasis, the migration of tumor cells to secondary sites that are different from the site of the original tumor.

The term “leukemia” includes malignancies of the hematopoietic cells of the bone marrow. Leukemias tend to proliferate as single cells. Examples of leukemias include acute myeloid leukemia (AML), acute promyelocytic leukemia, chronic myelogenous leukemia, mixed-lineage leukemia, acute monoblastic leukemia, acute lymphoblastic leukemia, acute non-lymphoblastic leukemia, blastic mantle cell leukemia, myelodyplastic syndrome, T cell leukemia, B cell leukemia, and chronic lymphocytic leukemia. Preferred leukemias include T cell malignancies, e.g., T cell leukemia and myeloma.

The invention provides therapeutic methods and compositions for the prevention and treatment of cancer and for the administration of a vaccine to a subject.

In one embodiment, the present invention contemplates a method of treatment, comprising: a) providing, i.e., administering: i) a mammalian patient particularly human who has, or is at risk of developing, cancer, ii) one or more molecules of the invention.

The term “at risk for developing” is herein defined as individuals with familial incidence of, for example, cancer.

The present invention is also not limited by the degree of benefit achieved by the administration of the fusion molecule. For example, the present invention is not limited to circumstances where all symptoms are eliminated. In one embodiment, administering a fusion molecule reduces the number or severity of symptoms of cancer. In another embodiment, administering of a fusion molecule may delay the onset of symptoms.

Typical subjects for treatment in accordance with the individuals include mammals, such as primates, preferably humans. Cells treated in accordance with the invention also preferably are mammalian, particularly primate, especially human. As discussed above, a subject or cells are suitably identified as in needed of treatment, and the identified cells or subject are then selected for treatment and administered one or more of fusion molecules of the invention.

The treatment methods and compositions of the invention also will be useful for treatment of mammals other than humans, including for veterinary applications such as to treat horses and livestock e.g. cattle, sheep, cows, goats, swine and the like, and pets such as dogs and cats.

For diagnostic or research applications, a wide variety of mammals will be suitable subjects including rodents (e.g. mice, rats, hamsters), rabbits, primates and swine such as inbred pigs and the like. Additionally, for in vitro applications, such as in vitro diagnostic and research applications, body fluids (e.g., blood, plasma, serum, cellular interstitial fluid, saliva, feces and urine) and cell and tissue samples of the above subjects will be suitable for use.

Vaccines

The preparation of vaccine compositions that contain the nucleic acid molecules or polypeptides of the invention as an effective ingredient is known to one skilled in the art. Typically, such vaccines are prepared as injectables, either as liquid solutions or suspensions; solid forms suitable for solution in, or suspension in, liquid prior to infection can also be prepared. The preparation can also be emulsified, or the protein encapsulated in liposomes. The active immunogenic ingredients are often mixed with carriers which are pharmaceutically acceptable and compatible with the active ingredient. The term “pharmaceutically acceptable carrier” refers to a carrier that does not cause an allergic reaction or other untoward effect in subjects to whom it is administered. Suitable pharmaceutically acceptable carriers include, for example, one or more of water, saline, phosphate buffered saline, dextrose, glycerol, ethanol, or the like and combinations thereof. In addition, if desired, the vaccine can contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents, and/or adjuvants which enhance the effectiveness of the vaccine. Examples of adjuvants which may be effective include but are not limited to: aluminum hydroxide, N-acetyl-muramyl-L-threonyl-D-isoglutamine (thr-MDP), N-acetyl-nor-muramyl-L-alanyl-D-isoglutamine (CGP 11637, referred to as nor-MDP), N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-(1′-2′-dip-almitoyl-sn-glycero-3-hydroxyphosphoryloxy)-ethylamine (CGP 19835A, referred to as MTP-PE), and RIBI, which contains three components extracted from bacteria, monophosporyl lipid A, trehalose dimycolate and cell wall skeleton (MPL+TDM+CWS) in a 2% squalene/Tween 80 emulsion. Other examples of adjuvants include DDA (dimethyldioctadecylammonium bromide), Freund's complete and incomplete adjuvants and QuilA. In addition, immune modulating substances such as lymphokines (e.g., IFN-g, IL-2 and IL-12) or synthetic IFN-g inducers such as poly I:C can be used in combination with adjuvants described herein.

Vaccine compositions of the present invention may be administered parenterally, by injection, for example, either subcutaneously or intramuscularly. The vaccine compositions can further be delivered by a gene gun. Additional formulations which are suitable for other modes of administration include suppositories, and in some cases, oral formulations or formulations suitable for distribution as aerosols. For suppositories, traditional binders and carriers may include, for example, polyalkylene glycols or triglycerides; such suppositories may be formed from mixtures containing the active ingredient in the range of 0.5 to 10%, preferably I to 2%. Oral formulations include such normally employed excipients as, for example, pharmaceutical grades of mannitol, lactose, starch magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, and the like. These compositions take the form of solutions, suspensions, tablets, pills, capsules, sustained release formulations or powders and contain 10% to 95% of effective ingredient, preferably 25 to 70%.

The nucleic acid molecules and proteins of the present invention can be formulated into the vaccine compositions as neutral or salt forms. Pharmaceutically acceptable salts include the acid addition salts (formed with free amino groups of the peptide) and which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or with organic acids such as acetic, oxalic, tartaric, maleic, and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroides, and such organic bases as isopropylamine, trimethylamine, 2-ethylamino ethanol, histidine, procaine, and the like.

Vaccine compositions are administered in a manner compatible with the dosage formulation, and in such amount as will be prophylactically and/or therapeutically effective. The quantity to be administered depends on the subject to be treated, including, e.g., capacity of the subject's immune system to synthesize antibodies, and the degree of protection or treatment desired. Suitable dosage ranges are of the order of several hundred micrograms effective ingredient per vaccination with a range from about 0.01 to 10 mg/kg/day, preferably in the range from about 0.1 to 1 mg/kg/day. Suitable regiments for initial administration and booster shots are also variable but are typified by an initial administration followed by subsequent inoculations or other administrations. Precise amounts of effective ingredient required to be administered depend on the judgment of the practitioner and may be peculiar to each subject. It will be apparent to those of skill in the art that the therapeutically effective amount the vaccine of this invention will depend, inter alia, upon the administration schedule, the unit dose of antigen administered, whether the vaccine is administered in combination with other therapeutic agents, the immune status and health of the recipient, and the therapeutic activity of the particular vaccine.

The vaccine can be given in a single dose schedule, or preferably in a multiple dose schedule. A multiple dose schedule is one in which a primary course of vaccination can include 1 to 10 separate doses, followed by other doses given at subsequent time intervals required to maintain and or reinforce the immune response, for example, at 1 to 4 months for a second dose, and if needed, a subsequent dose(s) after several months. Periodic boosters at intervals of 1 to 5 years, usually 3 years, are desirable to maintain the desired levels of protective immunity.

Immunization protocols have used adjuvants to stimulate responses for many years, and as such adjuvants are well known to one of ordinary skill in the art. Some adjuvants affect the way in which antigens are presented. For example, the immune response is increased when protein antigens are precipitated by alum. Emulsification of antigens also prolongs the duration of antigen presentation.

In one aspect, an adjuvant effect is achieved by use of an agent such as alum used in about 0.05 to about 0.1% solution in phosphate buffered saline. Alternatively, the antigen is made as an admixture with synthetic polymers of sugars used as an about 0.25% solution. Adjuvant effect may also be made by aggregation of the antigen in the vaccine by heat treatment. Aggregation by reactivating with pepsin treated (Fab) antibodies to albumin, mixture with bacterial cell(s) such as C. parvum or an endotoxin or a lipopolysaccharide components of Gram-negative bacteria, emulsion in physiologically acceptable oil vehicles such as mannide mono-oleate (Aracel A) or emulsion with a 20% solution of a perfluorocarbon used as a block substitute also may be employed.

Various polysaccharide adjuvants may also be used. For example, the use of various pneumococcal polysaccharide adjuvants on the antibody responses of mice has been described. The doses that produce optimal responses, or that otherwise do not produce suppression, should be employed as indicated. Polyamine varieties of polysaccharides are particularly preferred, such as chitin and chitosan, including deacetylated chitin.

EXAMPLES

It should be appreciated that the invention should not be construed to be limited to the examples that are now described; rather, the invention should be construed to include any and all applications provided herein and all equivalent variations within the skill of the ordinary artisan.

Materials and Methods

Fusion Gene Cloning and Protein Production

Generation of DNA vaccine constructs expressing murine MIP3α/CCL20, murine β-defensin 2 (mDF2β) and Hsp70 fused with tumor antigens (OFA-iLRP or sFv20) was previously described^(8, 9). Hsp70 cDNA was a generous gift from Dr. Thomas Lehner (Guy's Hospital, London, UK). Murine OFA-iLRP, (OFA, GeneBank # AF140348) was cloned from murine B cell A20 lymphoma (American Type Culture Collection, (ATCC) Manassas, Va.). All constructs were verified by the DNA sequencing (Fidelity Systems, Inc., Gaithersburg, Md.). To generate the DNA vaccine, the chemokine-OFA was cloned in pVAX1 plasmid (Invitrogen). Chemoattractant-OFA proteins were produced from IPTG-induced BL21(DE3) cells (Stratagene) using bacterial expression vector pET11d (Stratagene) and purified (>90% purity) from inclusion bodies as described previously^(8,15). The peptides iLR₅₈₋₆₆ (LLLAARAIV)⁶, MOPC-315 Ig₉₁₋₁₀₁ (ALWFRNHFVFGGGTK)¹⁶ were all synthesized by Peptide Technologies (Washington, D.C.) to a purity >99% by HPLC and amino acid analysis.

Cell Lines

The A20 B cell lymphoma (H-2^(d), OFA-iLRP positive), MOPC315 plasmacytoma (H-2^(d), OFA-iLRP negative) and EL-4 thymoma (H-2^(b), OFA-iLRP positive) cell lines were purchased from ATCC. The B6/129 macrophage cell line (H-2^(d), CCR6 positive by FACS analysis) was a generous gift from Dr. Howard Young (NCI, MD). Murine bone marrow (BM)-derived DC preparation was previously described¹⁷. Cells used on day 4-5 of cultivation, that usually yields iDCs¹¹.

Immunizations of Mice

All animals were bred or housed at the National Institute of Aging animal facility, Baltimore, Md. Animal care was provided in accordance with the procedures outlined in a Guide for the Care and Use of Laboratory Animals (NIH Publication No. 86-23, 1985). For tumor protection study, six- to eight-week old female BALB/C mice (ten per group) were immunized three times every two weeks by electroporating 25 μg DNA in 50 μl endo-free water intradermally (i.d.) into the base of tail using 4 mm-gapped electrodes and PA4000 electric pulse generator (Cyto Pulse Sciences, Inc., Linthicum, Md.) at the following settings: 2 pulses at 450V, 0.125 S and 0.05 mS. Two weeks after the last immunization, mice were challenged i.p. with 2×10⁵ A20 lymphoma cells and mice were followed for tumor survival. For therapy studies, six- to eight-week old female BALB/C mice (ten per group) were challenged i.p. with 2×10⁵ A20 lymphoma cells at day 0, and then immunized with DNA constructs at days 3, 8 and 18. Differences in survival between groups were determined by non-parametric logrank test (BMDP statistical software, Los Angeles).

Preparation of Immune Effector Cells, In Vitro Activation of T Cells

Mice were vaccinated s.c. twice at 3-wk intervals with 10 μg human iLR₅₈₋₆₆ peptide emulsified in 100 μl incomplete Freund's adjuvant (IFA). Three weeks after the second vaccination, splenocytes were cultured with 20 IU/ml rhIL-2 and 1 μg/ml corresponding peptide (irrelevant MOPC-315 Ig₉₁₋₁₀₁ or iLR₅₈₋₆₆, respectively) and used on days 5-7 after the initiation of the culture.

In Vivo T Cell Subset Depletions.

In vivo antibody depletions started 2 weeks after vaccination by treatment with three i.p. doses of 400 μg anti-CD8 mAb GK 2.43 or anti-CD4 mAb GK1.5 (NCI-FCRDC, Frederick, Md.), or normal rat IgG (Sigma) every other day two weeks after the last immunization, prior to tumor challenge. Depletion of lymphocyte subsets was assessed 1 week after final treatment by flow cytometry analysis of splenocytes from normal mice treated with these mAb in parallel⁸.

Chemokine Receptor Binding

The ligand binding-internalization assays were performed with iDC or splenocytes (1×10⁵) blocked with mouse serum in PBS containing 2% BSA. Fusion proteins (10-50 μg/ml) were incubated in complete medium for 1 h at 37° C. or at 4° C. To detect bound proteins, the cells were incubated with anti-c-myc mAb or isotype-matched, purified mouse IgG1, followed with a-mouse Ig-FITC mAb incubation (Jackson ImmunoResearch Laboratory, Bar Harbor, Me.) for 20 min each, and then fixed with 1% paraformaldehyde. The binding-internalization was assessed via flow cytometry on a FACScan (Becton Dickinson, Franklin Lakes, N.J.) using CellQuest software.

Intracellular Antigen Processing

Antigen presenting cells, splenocytes or iDC, from naïve BALB/c mice were incubated overnight with various concentrations of fusion protein (0.01-1 μg/ml). The treated APCs were subsequently irradiated (2000 Rad), washed twice with PBS to remove unbound proteins, and then cocultured for 24-48 h with specific effector cells from the iLR₅₈₋₆₆ (or irrelevant MOPC-315 Ig₉₁₋₁₀₁) peptide immunized mice. Some APCs were treated overnight with chemokine fused with various inhibitors: pertussis toxin (PTX, 2.5 ng/ml), sucrose (0.4M), brefeldin A (500 μM), chloroquine (50, 10 and 1 μM) and lactacystin (50, 10 and 1 μM). All reagents were purchased from Sigma.

Cytolytic Assay for Immune Splenocytes

Three per group female BALB/C mice were electroporated with plasmid constructs as described above or s.c. immunized with 10 μg iLR₅₈₋₆₆ peptide/IFA twice with two weeks intervals. Splenocytes were in vitro stimulated with 1 μg iLR₅₈₋₆₆ peptide or irrelevant MOPC315 peptide in complete RPMI 1640 with IL-2 for one week, then were mixed with target cells (1×10⁴), A20 lymphoma, MOPC315 and EL4. The cytotoxicity as lactate dehydrogenase release (LDH) in the cell supernatants was measured using the Cytotoxicity Detection Kit (Roche) following manufacturer's instructions at the sorbance measured at 570 nm with a 630 nm reference filter on a plate reader 680XR (Bio-Rad). The average values for wells performed in triplicate were used for calculations after the medium controls were subtracted. The percent-specific cytotoxicity was calculated as: percent cytotoxicity=(experimental−effector alone)−target spontaneous/target maximum−target spontaneous.

Confocal Microscopy

B6/129 cells (10⁵) were cultured overnight in covered glass bottom dishes (MatTek Corporation, Ashland, Mass., USA) as described elsewhere¹⁸. The slides were incubated on ice with 25 μg/ml MIP3α-fusion proteins in 10% FBS/RPMI. After two washes in ice-cold PBS, 10% FBS/RPMI warmed at 37° C. was added and slides were incubated at 37° C. for 0, 10, 30, and 60 minutes before fixation with 3.7% formaldehyde for 10 min and permeabilization with 0.2% Triton X-100 for 5 min at RT. Following primary Abs were used: anti myc mAb (clone 9E10, Sigma), and rabbit anti-LAMP-1 antibody (H-228) or rabbit anti-Clathrin HC (H-300, both from Santa Cruz Inc., Calif., USA), or rabbit anti-proteasome 20S subunit alpha-5 (Affinity BioReagents, Golden, Colo.). The secondary Abs, goat anti-mouse or goat anti-rabbit IgG, were conjugated to Alexa Fluor 488 or Alexa Fluor 568 (Molecular Probes Inc, Oreg., USA). After washing, a drop of Prolong anti-fade reagent (Molecular Probes) was added to each slide well, and images were acquired with a 63× objective on a Zeiss LSM 410 confocal system and processed using Adobe Photoshop.

Mice vaccinated with MIP3α/CCL20 fused with OFA-iLRP display long lasting CD8 T cell-dependent protective responses. Specifically, immune mice rejected challenge with synergetic tumor cells even after 9 months (see FIG. 15A-D).

Results and Discussion

DNA vaccines expressing OFA fused to chemo-attractants elicit potent anti-A20 lymphoma protection. Embryonic antigen OFA-iLRP (OFA) is an attractive target for cancer immunotherapy, as it is abundantly expressed in various malignancies, including murine A20 lymphoma, and not found in normal adult tissues¹. Initial attempts to induce anti-A20 lymphoma responses in nave BALB/C mice immunized with plasmid DNA expressing OFA failed, due to poor immunogenicity of the antigen. Therefore, to render OFA immunogenic through the CCR6-mediated targeting of iDCs, constructs which expressed OFA fusions with mDF2β (pmDF2β-OFA) or MIP3α/CCL20 (pMIP3α-OFA) were generated. Ten per group naïve BALB/C mice were immunized with either pmDF2β-OFA or with pmDF2β-sFv20, a positive control construct that encoded mDF2β fusion to A20-specific Ig fragment (single chain Fv) shown to be immunogenic⁹. Then, two weeks after the last immunization, mice were challenged with a lethal dose of A20 lymphoma cells. Almost all mice mock immunized with PBS succumbed to cancer (PBS, FIG. 1a ). In contrast, mice immunized with pmDF2β-OFA or pmDF2β-sFv20 acquired significant protection against A20 lymphoma (p<0.05, as compared with PBS treated mice, FIG. 1a ). The response required targeting of CCR6, as control vaccines that expressed OFA fused to mutant MIP3α, which did not bind CCR6 due to a single point mutation¹¹, failed to protect (pMIP3α-D-OFA, see FIG. 4). Thus, pmDF2β-OFA is as potent as the Id vaccine (pmDF2β-sFv20) and induces comparable protective anti-B cell lymphoma responses. However, unlike Id, OFA-based vaccines would not require individual formulations for each patient; instead, they might be used for the treatment of any OFA-expressing cancers.

Tumor protection is not improved by use of multiple TAA-encoding vaccines. Since either of the vaccines that expressed different tumor antigens, pmDF2β-sFv20 or pMIP3α-OFA, elicited comparable responses, we tested whether they would also act additively when used together (pmDF2P-sFv20+pMIP3α-OFA). As shown in FIG. 1a , mice were protected against A20 lymphoma at almost the same level regardless of whether they were immunized with the vaccine mixture or with a single antigen-expressing vaccine (see pmDF2β-sFv20+pMIP3α-OFA vs. pmDF2β-OFA or pmDF2β-sFv20, FIG. 1a ). Thus, immune responses elicited against a single TAA can be sufficiently high to protect against tumors, and use of additional antigens may not be necessary or beneficial.

Tumor protection depends on induction of effector CD8⁺ T cells. Mice immunized with pmDF2β-OFA or pMIP3α-OFA generated not only OFA-specific IgG1 antibodies (open triangle, FIG. 1b ), but also significant levels of IgG2a antibody (closed triangle, FIG. 1b ), indicating that they might produce Th1 responses¹⁹. Moreover, mice immunized with the vaccines generated cytolytic T cells (CTLs) capable of specific killing of A20 tumor cells in vitro (FIG. 2a ). The CTLs were specific to OFA, as they did not lyse irrelevant HLA-matched MOPC315 cells, which did not express OFA (FIG. 2a ). The response was dependent on the ability of the vaccine to target CCR6, since splenocytes from mice immunized with the construct expressing OFA fused to a mutant MIP3α (pMIP3α-D-OFA, FIG. 2a ) did not kill A20 lymphoma cells. Since mice immunized with pMIP3α-D-OFA were also not protected (FIG. 4), it is tempting to speculate that the protection was mediated by these CTLs. To study this, CD8⁺ or CD4⁺ effector cells were depleted in mice immunized with pMIP3α-OFA by injecting specific antibodies prior to the challenge with A20 lymphoma cells. Injections of isotype-matched irrelevant IgG (pMIP3α-OFA+IgG, FIG. 2b ), or the depletion of effector CD4⁺ T cells (pMIP3α-OFA+αCD4 Ab, FIG. 2b ) did not have any effects and mice immunized with pMIP3α-OFA remained protected. In contrast, the protection was completely abolished in mice that were depleted of effector CD8⁺ T cells (pMIP3α-OFA+αCD8 Ab, FIG. 2b ). Taken together, these data clearly indicate that, as we also reported for Id-mediated anticancer protection⁹, the protection was primarily dependent on the activation of cellular immunity, particularly effector CD8⁺ T cells, but not humoral responses despite the fact that both Id and OFA-iLRP are expressed on the cell surface. Thus, the breadth of the CCR6-targeting chemoattractant-based OFA vaccines is in their ability to elicit tumor-specific CD8⁺ cytolytic T cell responses.

The CCR6-targeted OFA is efficiently taken up and cross-presented to MHC class I molecules. CCR6 would efficiently internalize upon binding with its ligands MIP3α or mDF2β⁹. Similarly, unlike control OFA constructs (OFA alone or fused with mutant chemokines), MIP3α-OFA or mDF2β-OFA were taken up through CCR6 expressed on murine BM iDC (data not shown), suggesting that the CTL responses observed might be due cross-presentation of the internalized OFA. To test this, naïve BM iDCs from BALB/C mice were incubated overnight with nM concentrations of purified recombinant MIP3α-OFA or mDF2β-OFA proteins. Then, after extensive washing and irradiation steps, the cells were mixed with immune splenocytes from syngeneic mice immunized with the peptide OFA-iLRP₅₈₋₆₆ in IFA, which elicited CTLs capable of specific killing of A20 lymphoma cells in vitro, but not control HLA-matched MOPC315 cells that did not express OFA (FIG. 2a ). The assumption was that, if CCR6 mediated cross-presentation, APCs incubated with MIP3α-OFA or mDF2β-OFA, but not free OFA, would stimulate the OFA-iLRP₅₈₋₆₆ peptide-specific T cells. As shown in FIG. 3a , only iDCs incubated with as little as 100 ng/ml MIP3α- or mDF2β-OFA fusion proteins induced significant IFNγ secretion from the OFA peptide-specific T cells, suggesting that chemoattractant fused OFA was processed and presented to MHC class I molecules. Control DCs incubated with MIP3α-OFA or mDF2βsFv20 (irrelevant tumor antigen fusions, data not shown) did not stimulate the splenocytes, ruling out non-specific effects from the chemoattractants used. Thus, these data indicate that MIP3α-OFA was efficiently cross-presented, which involved an active receptor-mediated process, as pertussis toxin (PTX, which abrogates Giα-coupled receptor signaling, FIG. 3a ), or high hypertonic sucrose solution (which inhibits clathrin-coated pit dependent endocytosis, data not shown) completely abolished ability of APCs to stimulate T cells. Similarly, chloroquine, the serine and cysteine protease inhibitor of lysosomal protein degradation, or brefeldin A, a fungal metabolite that inhibits vesicle transport of newly synthesized MHC class molecules between the endoplasmic reticulum (ER) and Golgi²⁰, completely abrogated the response (FIG. 3a ), indicating the importance of lysosomal activity in the chemoattractant-induced MHC class I presentation of OFA. Proteins were shown to be processed directly within endosomal/lysosomal compartments and loaded to MHC class I molecules, which resided in classical MHC class II compartments, utilizing TAP-independent and NH₄Cl-sensitive cross-presentation pathways^(21,22). However, the CCR6-targeted OFA utilized classical cross-presentation pathway in the cytosol, since lactacystin, a specific inhibitor of proteasomal protein degradation, completely abrogated the response (FIG. 3a ). The pharmacological inhibitors used in this experiment did not cause non-specific suppressions, since they did not affect stimulation of T cells induced by iDCs that were directly pulsed with OFA-iLRP₅₈₋₆₆ peptide (that did not require internalization and processing, FIG. 3a ). These findings are supported by the confocal microscopy studies demonstrating that MIP3α-fusions, prior to internalization, were colocalized with clathrin vesicles on the cell surface (0 min, FIG. 3b ). However, within 10 min after internalization of MIP3α-fusions, they were found in lyzosomes or colocalized with proteasomes in the cytosol (FIG. 3b ). The processed MIP3α-fusions were presumably degraded within 1 hour after the internalization by lyzosomal enzymes and proteasomes (since the colocalized signal disappeared by 60 min incubation, FIG. 3b ). Presumably, 60 min is sufficient to present processed peptides to MHC molecules, since iDCs incubated with MIP3α-OFA for as little as one hour were capable of stimulating immune T cells (though at much lower levels, data not shown). The peptides were presented onto H-2^(d) molecules, as the blocking antibody, but not control isotype matched antibody, completely abolished ability of iDCs incubated with MIP3α-OFA or mDF2β-OFA to stimulate immune T cells (FIG. 3c ). Taken together, these data clearly demonstrate that potency of MIP3α-OFA or mDF2β-OFA is in their ability to use the CCR6-mediated uptake, processing and cross-presentation pathways. As a result, the vaccine elicited both CD4⁺ T helper, as recently reported¹⁰, and cytolytic CD8⁺ T cell responses leading to protection from A20 lymphoma, known for its resistance to immunotherapy^(23;24). Thus, it is tempting to speculate that lack of tumor protection in mice immunized with OFA-iLRP₅₈₋₆₆ peptide/IFA (data not shown) might be attributed to the absence of the T helper responses, although they generated CTLs capable of killing of A20 tumor cells in vitro (FIG. 2a ).

Conclusion. The superiority of the CCR6-targeting OFA vaccines are in their ability to elicit not only CD8⁺ CTLs (that recognized multiple OFA epitopes), but also in induction of Th1 helper CD4⁺ T cell responses.

Since this otherwise non-immunogenic OFA-iLRP is not expressed in normal adult tissues, the vaccine formulation can be also utilized as a preventive vaccine for induction of protective antitumor memory responses in healthy people at high risk for cancer.

Moreover, the vaccines of the invention have been shown to cause long lasting protective responses in mice.

Incorporation by Reference

The contents of all references, patents, pending patent applications and published patents, cited throughout this application are hereby expressly incorporated by reference.

Equivalents

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

REFERENCES

The following documents are referred to above and generally specified by superscript number corresponding to the reference number set forth below. Thus, for example, the first document of Cogin et al. Anticancer Res. 19:5535-5542 is referred to above with a superscript 1.

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What is claimed is:
 1. A polypeptide comprising a tumor-associated embryonic antigen translationally fused with a CCR6-targeting chemoattractant ligand, wherein the tumor-associated embryonic antigen is OFA-iLRP, and the chemoattractant ligand is β-defensin DF2β, wherein the polypeptide comprises the amino acid sequence of SEQ ID Nos: 2 or
 20. 2. A polypeptide comprising a tumor-associated embryonic antigen translationally fused with a chemoattractant ligand, wherein the tumor-associated embryonic antigen is OFA-iLRP and the chemoattractant ligand is MIP3α/CCL20, wherein the polypeptide comprises the amino acid sequence of SEQ ID NOs: 4, 12, 18, 22, 24, or
 30. 3. The polypeptide of claim 1, further comprising a polypeptide linker between the tumor-associated embryonic antigen and the chemoattractant ligand.
 4. A cancer vaccine comprising the polypeptide of claim
 1. 5. A kit comprising the vaccine of claim 4 and instructions for use. 